This invention relates to a swivel for a rotary drilling machine or rig and more particularly to a swivel for use with a reverse rotary drilling rig.
In rotary drilling machines, the swivel provides a means for forcing drilling fluid from stationary pump connections into the rotating drill column while the latter is suspended in the well. Being a part of the mechanism by which the drill column is suspended from the derrick or tower crown block, the swivel must be of massive construction so that it is capable of supporting the full weight of the drill column while it is being rotated by the rotary table.
Conventional swivels comprise several parts, all of which are contained within or attached to a heavy housing or the like supported by a bail or the like which is connected to the derrick crown block. In smaller drilling rigs, the upper end of the Kelly bar is vertically movably supported on the tower. Roller bearings in the body of the swivel support the rotating element which is attached at its lower end to the upper end of a Kelly bar. A washpipe extends downwardly into the upper end of the rotating sleeve which is ordinarily connected at its upper end with a gooseneck or the like which is threaded for connection with a flexible hose designed to carry high-presssure drilling fluid from the pump manifold. Bearings are provided between the rotating and non-rotating portions of the swivel and are immersed in oil and sealed to prevent drilling fluid from coming into contact with the bearings. In conventional rotary drilling operations, drilling fluid is supplied from the pump manifold to the flexible hose and thence downwardly into the washpipe and supplied to the Kelly bar and then to the interior of the drill column. The drilling fluid is forced from the drill bit and the drilling fluid returns to the fluid reservoir between the drill column and the wall of the well.
In recent years, reverse rotary drilling rigs have been employed wherein the drilling fluid is pumped downwardly between the wall of the well and the exterior surface of the drill column and is then forced upwardly through the drill column to the pump manifold or reservoir. In other words, the direction of flow of the drilling fluid is reversed from that of conventional rotary drilling machines. A severe problem has been encountered with the swivels in reverse rotary drilling rigs due to the fact that the reverse swivels presently available employ extremely complicated packing chambers which are almost impossible to disassemble and repack in a short period of time. Additionally, the packing chambers on the available reverse swivels do not effectively prevent drilling fluid from coming into contact with the bearings in the swivel and the bearings are quickly ruined which requires the replacement of the bearings which is obviously time consuming and expensive.
Therefore, it is a principal object of the invention to provide an improved swivel for a rotary drilling machine.
A still further object of the invention is to provide an improved swivel for a reverse rotary drilling machine.
A still further object of the invention is to provide a swivel for a reverse rotary drilling rig which can accommodate any type of drilling fluid whether it be air or mud.
A still further object of the invention is to provide a swivel for use with a drilling rig which may be of the air reverse, reverse drilling or conventional rotary drilling types.
A still further object of the invention is to provide a swivel wherein packing material may be conveniently added to the packing gland.
A still further object of the invention is to provide a swivel which is easily and quickly diassembled in the field to replace worn or damaged components.
A still further object of the invention is to provide a swivel of the type described which is economical of manufacture and durable in use.
These and other objects will be apparent to those skilled in the art.